GIMPO, South Korea South Korea's initial retaliation to the North's latest nuclear test was a mix of K-pop, scathing commentary on its nuclear programme and derision of the ruling family's penchant for costly clothes and luxury handbags.

Over the hills by Gimpo city bordering the North, broadcasts from one of 11 banks of high-power speakers set up along the border spared no criticism of leader Kim Jong Un, who was believed to have turned 33 on Friday.

"Clothes for Kim Jong Un and Ri Sol Ju cost tens of thousands dollars each and her purse is worth thousands of dollars too," a male announcer said. Ri is Kim's wife.

The broadcast can travel 24 km (15 miles) at night and 10 km in daylight, far enough to reach beyond soldiers at the border to civilians to the north.

To the outside world, the idea that broadcasts that also showcase freedom and democracy, and how people are allowed to enjoy love and life, can anger a country enough to risk going to war might seem preposterous.

But North Korea sees them as an attack on the dignity of its leader and political system, and was provoked enough the last time the South used a tactic the North calls "an open act of war", in August, to launch an artillery strike across the border.

South Korean officials said stopping the broadcasts was the main reason the North agreed at that time to end an armed standoff and express regret over a landmine explosion that injured South Korean soldiers.

PSY OPS

The South Korean military's psychological department produces content for the FM radio station Voice of Freedom, which from noon (0300 GMT) on Friday was channelled to the speakers randomly for up to six hours a day.

Early in the broadcast, the South criticised the North's claim on Wednesday to have conducted its first hydrogen bomb test. The U.S. government and other experts doubt that the North has achieved such a technological advance since its last nuclear test in 2013.

"The nuclear test is making North Korea more isolated and turning it into the land of death," an announcer said. Another said Kim's signature policy of jointly boosting the economy and nuclear capability "has no realistic value".

North Korean defectors have said the broadcasts had left a lasting impression that there were songs without an ideological message, that spoke only of love.

Commentary, news and weather from around the world are mixed in with such K-pop hits as "Let us love each other" and South Korean boy band BIGBANG's megahit "Bang Bang Bang".

(Additional reporting and writing by Ju-min Park; Editing by Jack Kim, Robert Birsel)

This story has not been edited by Firstpost staff and is generated by auto-feed.